HP 3000 Manuals HP 3000 Manuals
Types of Data
The treatment of data types by this COBOL system is associated with the
action of the file conversion utility, convert3. This COBOL system
always allocates the same number of bytes to the item in question, but
may redefine its contents when it is converted. Therefore, you must be
aware that if these items are redefined, and the program logic expects to
find a certain binary value in the redefinition, you may not receive the
behavior you are expecting at run-time. You must also note that at
run-time, this COBOL system may treat the ON SIZE ERROR clause
differently from the RM/COBOL system. See Chapter 7 for further
details.
The following sections define how this COBOL system treats COMPUTATIONAL,
COMPUTATIONAL-1 and COMPUTATIONAL-6 types of data.
COMPUTATIONAL (COMP) Data Types
This COBOL system treats any COMP data items in your RM/COBOL source
program as the standard VS COBOL DISPLAY format. The difference in the
internal representation of such data in the two systems is that this
COBOL system always sets the most significant four bits of each byte to
the value 3, while the RM/COBOL system always sets such bits to the value
0.
For example, under the RM/COBOL system:
PIC 999 COMP VALUE 123
is held in three bytes as hexadecimal value 01 02 03
while under this COBOL system:
PIC 999 VALUE 123
is held in three bytes as hexadecimal value 31 32 33.
COMPUTATIONAL-1 (COMP-1) Data Types
For each data item declared as USAGE COMP-1 in your RM/COBOL source
program, regardless of its picture string, this COBOL system allocates a
2-byte signed binary data item. This data item is capable of holding a
hexadecimal value in the range -32768 to +32767. That is, this COBOL
system treats each RM/COBOL USAGE COMP-1 data item as though it had a
standard VS COBOL picture string of S9(4) COMP. See your Language
Reference for details on the standard VS COBOL language.
COMPUTATIONAL-6 (COMP-6) Data Types
This COBOL system treats any COMP-6 data items in your RM/COBOL source
program as the standard VS COBOL COMP format. If, as a result of this,
less data space is allocated to each item than would be under the
RM/COBOL system, this COBOL system pads the space with a byte containing
a zero, as shown in the following table:
Table 6-1. COMP-6 to COMP Conversion
----------------------------------------------------------------------------------
| | | |
| RM COMP-6 | Bytes allocated when | Number of bytes containing |
| PICTURE | converting to VS COBOL COMP | leading zeros required to |
| clause | PICTURE clause | precede COMP PICTURE clause |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(1) | 1 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(2) | 1 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(3) | 2 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(4) | 2 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(5) | 3 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(6) | 3 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(7) | 4 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(8) | 4 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(9) | 5 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(10) | 5 | NONE |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(11) | 5 | 1 |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(12) | 5 | 1 |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(13) | 6 | 1 |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(14) | 6 | 1 |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(15) | 7 | 1 |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(16) | 7 | 1 |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(17) | 8 | 1 |
| | | |
----------------------------------------------------------------------------------
| | | |
| 9(18) | 8 | 1 |
| | | |
----------------------------------------------------------------------------------
Note that the padding byte precedes the converted field, and is therefore
included in any redefinition of group fields which contain the converted
field. However, the padding byte would not be included if you redefined
only the converted field. If you wish to ensure that the padding byte is
included in the redefinition of the converted field, you must add a field
at a higher level immediately before the converted field, and redefine
this new field instead.